Reverse flow check valve



Oct. 26, 1965 vlRTu 3,213,761

REVERSE FLOW CHECK VALVE Filed May 25, 1964 w fnjentor' Eugene 'l/lri Q Q %M,

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United States Patent 3,213,761 REVERSE FLOW CHECK VALVE Eugene P. Virtue, Tinley Park, IIL, assiguor to International Harvester Company, Chicago, 11]., a corporation of New Jersey Filed May 25, 1964, Ser. No. 370,018 8 Claims. (Cl. 91414) This invention relates to hydraulic valve mechanisms, but more particularly it is directed to reverse flow check valves employed in association with a bank of opencenter-type control valves.

An important object of the present invention is to provide an improved, highly effective and simplified reverse flow check valve for a hydraulic circuit.

Another object is to provide a reverse flow check valve employing slidable sleeve means open at opposite ends and adapted for engaging a fixed valve seat means at one end thereof to restrict flow therethrough to one direction.

A further object is to provide a novel reverse flow check valve means wherein a sleeve member slidably disposed in a fluid carrying passage is operative for seatably engaging a fixed valve seat in said passage for interrupting flow therethrough when the pressure in an interconnected hydraulic circuit exceeds the inlet pressure to said check valve means.

A still further object is to provide, in a hydraulic systern operating a plurality of hydraulic circuits at different pressures from a common source of fluid pressure, a unique sleeve-type check valve means operative to prevent reverse flow in the higher pressure circuit thereof when the pressure therein exceeds that of the lower pressure circuit thereby preventing such excess pressure being reflected in and attendant thereto affecting the lower pressure circuit of the system.

Further objects and advantages of the present invention will be apparent from the full description, reference being had to the accompanying drawing wherein a preferred form of the present invention is clearly shown.

The lone figure is a part schematic and part sectional view of a hydraulic system illustratively incorporating therein the proposed reverse fiow check valve of the present invention.

Referring now to the drawing it will be seen that the present invention has been illustrated, in a generally schematic form, by way of association with a hydraulic system having a plurality of individual control valves arranged in a multiple bank and utilized for individually controlling operation of a plurality of work-producing fluid motor devices A typical example of such an arrangement is readily found in an earthworking machine wherein a boom carrying a bucket operates under control of one valve in a high pressure circuit while the bucket is usually operated for tilting under the control of another valve in a circuit operated at somewhat lower pressure.

A hydraulic pump 10 of conventional construction has the inlet thereof communicatively connected by a conduit 11 to a fluid reservoir 12, while the outlet or pressure side of said pump is connected by a conduit 13 to the inlet 14 of a manifold tower structure 15. Said manifold tower is arranged in a multiple bank arrangement with control valves 16 and 17 and is disposed so that certain ports of these components are aligned in an abutting and direct communication with certain ports of the next adjacent component or unit, as is well understood, when the components or units are assembled into an operative control valve assembly. Since the hydraulic system is generally similar to and the control valves 16 and 17 identical in construction with the disclosure illustrated ice and described in US. Patent 2,939,288 it is believed no useful purpose would be served by presenting herein any elaborate description of the details thereof, inasmuch as reference may be had to said patent for any further explanation desired of the specific construction and operation thereof. Suflice it to say that each such control valve is individually operative independently of one another to control the operation of an individually associated hydraulically actuated device in the manner heretofore described in detail in said patent.

An outlet or supply port 18 of said manifold tower communicates with port 19 of valve 16 and a Work port 20 of said valve is connected by a conduit 21 with one end of a fluid motor 22 while the opposite end of said motor is connected by a conduit 23 with a Work port 24 of valve 16. Another outlet or supply port 25 of manifold tower 15 communicates with a port 26 of valve 16, while an oppositely disposed port 27 of said valve communicates with a port 28 of valve 17. A work port 29 .of the latter valve is connected by a conduit 30 with one end of a fluid motor 31 and the opposite end of said motor is connected by a conduit 32 with a work port 33 of valve 17. An open-center control port 34 of manifold 15 communicates with a port 35 of valve 16 while an oppositely disposed port 36 thereof communicates with a port 37 of valve 17, and a port 38 of valve 16 communicates with a port 39 of valve 17. A conduit 40 interconnects the outlet ports 41, 42 of valve 17 and a passage 43 interconnects ports 44, 45 of this valve, while port 44, in turn, communicates with a port 46 of valve 16. A passage 47 interconnects ports 48 and 49 of valve 16 and port 48 in turn, communicates with a safety release or dump port 50 of manifold tower 15.

The manifold tower structure 15 may include a casing or body member 51 with a fluid inlet port 14 therein opening into a passage 52 which communicates by Way of a bore-like passage 53 with supply port 25 while a passage 54 which communicates with port 34 and a borelike passage 55 communicates with supply port 18. A generally conventional safety valve 56 at one end of passage 52 communicates on the release side thereof by way of a passage 57 with the safety release or dump port 50.

Now in accordance with the more specific teachings of the present invention port opening 18 is provided adjacent an outer end thereof with an annular recess 58 which has an O-ring type fluid seal 59 positioned against the outer periphery thereof and this seal in turn, is diametrically supported by a rigid metallic ring 60 positioned within an opening in said O-ring. Slidably positioned within the adjacent bore-like passage 55 is an open-ended tube or sleeve-like member 61 the interior diameter of which is less than that of ring 60 so as to provide an annular surface area 62 facing the port opening 18 and, as indicated, this latter annular surface may be inwardly bevelled or chamfered. The opposite end edge of sleeve member 61 is also inwardly bevelled or chamfered as shown at 63 for purposes which will presently be apparent. Spaced from the end 63 of said sleeve is a generally circular valve member 64 which is suitably fixedly mounted in body member 61 adjacent a wall portion of passage 52. A bevelled or chamfered end edge area 65 on the outwardly projecting end of valve member 64 provides a valve seat adapted to accommodate in close fit relationship the chamfered end edge 63 of sleeve member 61. Port opening 25, also, is provided with an annular recess such as 58a which has an O-ring type fluid seal 59a positioned against an outer periphery thereof and this seal, in turn, is diametrically supported by a rigid metallic ring 60a positioned within an opening in said latter O-ring. Slidably positioned within the adjacent bore-like passage 53 is a spaced valve member 64a.

similar open ended tube or sleeve-like member 61a having an annular inwardly chamfered surface 62a thereon. An opposite end edge of sleeve 61a is inwardly chamfered at 63a while spaced therefrom and fixedly mounted in the wall of passage 52 is a generally circularly A chamfered area 65a on the outer end edge of said latter valve member provides "a valve seat adapted to accommodate in close fit relationship the chamfered end edge 63a of sleeve member 61a. Additional sealing rings 66, 67 may be provided for the respective port openings 50 and 34, as is well understood. It will also be understood, of course, that suitable means (not shown) may be provided for attaching the manifold tower unit 15 to the next adjacent valve unit in the multiple bank. Suitable means such as the shifter operating members 68 and 69 may be provided as is well understood for the respective valves 16 and 17.

Operation Normally fluid under pressure is supplied from pump by way of conduit 13 to manifold tower 15 whereupon it is directed as required through supply ports 18 and and control port 34 to the respective control valves 16, 17 and, in turn, the fluid motors 22 and 31. With control valves 16 and 17 in the operative positions illustrated in the drawing fluid under pressure may be directed from control valve 16 by way of conduit 21 to one end of fluid motor 22 or from control valve 17 by way of conduit to an opposite end of fluid motor 31. Under such circumstances return flow from motor 22 would be accomplished by way of conduit 23 and from motor 31 by way of conduit 32. Assume now that fluid motor 22 is in a circuit operated at relatively high pressure, as for example in the order of 1500 psi. while fluid motor 31 is in a circuit operated at a considerably lower pressure for example 800 p.s.i. In this instance, since the upstream end surface area of sleeve valve member 61a exposed to the inlet pressure in passage 52 is greater than that of downstream area 62a at the opposite end of said sleeve, the sleeve will be maintained in abutting relation with the associated metal ring member 60a and fluid flow from inlet 14 will follow the path of least resistance and flow through the respective sleeve 61a and supply port 25 through valves 16 and 1 7 and conduit 30 to operate the fluid motor 31. At the same time since fluid motor 22 requires a much higher pressure there would be a tendency toward a reversal of flow through control valve 16 from the latter motor thereby causing said motor 22 to move in an opposite direction to that called for. When this occurs, since the efiective pressure exerted on the area 62 exposed to the higher pressure will be greater than the effective pressure exerted on the opposite end area of sleeve 61, it will cause the sleeve member 61 to slide into engagement with the proximate valve seat 65 whereupon flow through the respective sleeve member 61 will be interrupted and movement of fluid motor 22 will be stoped, thereby preventing the fluid pressure in the higher pressure circuit from causing a cross flow that would be reflected in and attendant thereto cause an undesirable reaction in the lower pressure circuit which includes the fluid motor 31. Now when the fluid pressure in passage 52 reaches a value greater than that in port 18, such as would occur when the control valve 17 was moved to an inoperative or neutral position, the pressure exerted against the upstream end edge of sleeve member 61 will exceed that exerted against the downstream end edge of said sleeve and the sleeve will thereupon be moved away from the valve seat 65 and fluid flow will be resumed to the fluid motor 22 by way of control valve 16. Should the pressure requirements to actuate the respective fluid motors be reversed the sleeve member 61a would then be moved to its seating position with valve seat 65a and flow through port 25 which would then be the high pressure port would be inter- 4 rupted. Furthermore, if one of the two circuits in th system was always operated at a higher pressure than the other circuit it will be appreciated that only one such reverse flow check valve device would be required and that, of course, would be positioned in the fluid flow passage to the high pressure circuit.

The present invention also envisages using such a reverse flow check valve device in a single hydraulic circuit ot prevent reverse flow in event of difliculty in maintaining the required pressure from an associated source of fluid pressure.

In the event the pressure in passage 52 exceeds a pre determined maximum value the safety valve 56 will open to dump or release such excess to the reservoir 12 by way of return conduit 40.

From the above it will be apparent a simplified, novel and highly effective reverse flow check valve has been provided for use with a hydraulic system and is especially advantageous in a system having circuits therein operated at different pressures. While only one form of the invention has been shown, it will be obvious to those skilled in the art that it is not so limited, but is suscepti'ble of various changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What is claimed is:

1. In a hydraulic system having a source of fluid pressure and individual control valve means controlling a plurality of hydraulic circuits, reverse flow check valve means, comprising: a body member; means forming fluid passages in said body member communicatively connecting said source with each of said circuits; sleeve valve means disposed one in each said passage slidably operative between an open position permitting fluid flow through the respective passage, and a closed posit-ion interrupting fluid flow therethrough; one of said sleeve valve means being operative responsive to development of a pressure in the respectively connected circuit greater than the pressure in the other of said circuits for closing the respective said one sleeve valve means and interrupting flow of fluid therethrough.

2. In a hydraulic system having a source of fluid pressure and a plurality of hydraulic circuits including a separate valving means for controlling operation of each such circuit and wherein one of said circuits is operated at a higher pressure than another one of said circuits, a reverse flow check valve, comprising: a body member having an inlet adapted for fluid communication with the source of fluid pressure, a plurality of outlet ports adapted for fluid communication with the respective plurality of circuits; means in said body forming fluid passages communicatively connecting said inlet and said outlet ports; a sleeve valve member slidably disposed in the outlet port communicatively connected to the circuit operated at the higher pressure and constructed for accommodating fluid flow therethrough from said inlet; means providing a valve seat mounted in the said fluid passage communicating with the higher pressure outlet port and disposed for seating engagement with an up stream end edge portion of said sleeve member for interrupting flow of fluid therethrough; said sleeve valve member being slidably operative for interrupting fluid flow therethrough when the pressure in the associated outlet port exceeds that in the associated fluid passage from said inlet port.

3. In a hydraulic system having a source of fluid pressure and a plurality of hydraulic circuits including a separate valving means for controlling operation of each such circuit, reverse flow check valve means, comprising: a manifold member having an inlet adapted for fluid communication with the source of fluid pressure, first and second outlet ports adapted for fluid communication with the respective first and second circuits; means in said manifold forming a fluid passage communicatively interconnecting said inlet and outlet ports; first and second sleeve means slidably disposed one each in the respective first and second outlet ports and arranged for accommodating fluid flow therethrough from said inlet to said outlet ports; first and second valve seat means mounted in said fluid passage and disposed for seatably engaging an end edge portion of a respective one of said sleeve members for interrupting flow of fluid through a respective sleeve member; one of said sleeve members being slidably operative for interrupting fluid flow therethrough when the pressure in the hydraulic circuit associated with said respective sleeve member exceeds that of the other of said hydraulic circuits wherefore back flow of fluid from the higher to the lower pressure circuit is prevented.

4. A hydraulic system having a source of fluid pressure, a first hydraulic circuit including valving means and a hydraulically actuated device and a second hydraulic circuit including valving means and a hydraulically actuated device and wherein one of said circuits is operated at higher pressure than that of the other such circuit, reverse flow check means, comprising: a manifold member having an inlet port therein adapted for fluid flow connection with the source of fluid pressure, first and second outlet ports adapted for fluid flow communication With the respective first and second circuits; means in said manifold forming a fluid passage communicatively interconnecting said inlet and outlet ports; first and second sleeve means slidably disposed in the respective first and second outlet ports and having openings therein for passage of fluid therethrough from said inlet port; a retainer ring means positioned in each said outlet port; first and second valve seat means in said fluid passage proximate the respective first and second sleeve means; said sleeve means being slidable between a position of abutting engagement at the downstream end thereof with a respective retainer ring to permit fluid flow through the associated outlet port and a position of abutting engagement at the upstream end thereof with a respective valve seat means for interrupting fluid flow through the associated outlet port; the sleeve associated with the outlet port communicatively connected to the circuit operated at the higher pressure being slidably operative responsive to actuation of said latter circuit concurrent with actuation of the other circuit thereof for seatably engaging the upstream end of said latter sleeve with a proximate valve seat for interrupting fluid flow through the respective sleeve whereby back flow from the higher to the lower pressure circuit is prevented.

5. The structure described in claim 4 further characterized in that each outlet port opening is circular in cross section, and the respective sleeve member positioned therein is tubular in form with both ends open and having opposite interior end edges thereof inwardly chamfered, and further in that each said valve seat means is circular in cross section and provided with a chamfered edge portion disposed for seatably engaging the chamfered upstream end edge portion of a respective sleeve member.

6. Th structure described in claim 4 further characterized in that the interior diameter of each of said retainer ring means is larger than the interior diameter of the associated sleeve means whereby a portion of the downstream end edge surface of each said sleeve means is constantly exposed to the pressure of the fluid flow within the respective sleeve means.

7. The structure described in claim 4 and further characterized in that each of said sleeve means is axially slidable along a longitudinal axis thereof.

8. A reverse flow check valve, comprising: a body member having an inlet port opening therein adapted for fluid flow connection with a source of fluid pressure, and an outlet port opening adapted for fluid flow connection to a hydraulic circuit; means in said body member forming a fluid passage communicatively interconnecting said inlet and outlet port openings; sleeve means slidably disposed in said outlet port opening and having an opening therein for passage of fluid therethrough from said inlet port opening; abutment means in said outlet port opening disposed for abutting engagement with a portion of a downstream end edge of said sleeve when the pressure at the upstream end of said sleeve exceeds the pressure at the downstream end thereof and having the remainder of said latter end edge portion exposed to the flow of fluid through the sleeve; means fixedly positioned in said fluid passage providing a valve seat for seatably engaging an upstream end edge of said sleeve member; the remainder end edge portion of said sleeve being subjected to the force of fluid pressure therein for slidably moving said sleeve to elfect a seating engagement with said valve seat and interrupting flow through said sleeve when the eflective pressure against the downstream end edge of said sleeve exceeds the effective pressure at the upstream end edge thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,939,288 6/60 Moyer 91-414 SAMUEL LEVINE, Primary Examiner. 

1. IN A HYDRAULIC SYSTEM HAVING A SOURCE OF FLUID PRESSURE AND INDIVIDUAL CONTROL VALVE MEANS CONTROLLING A PLURALITY OF HYDRAULIC CIRCUITS, REVERSE FLOW CHECK VALVE MEANS, COMPRISING: A BODY MEMBER; MEANS FORMING FLUID PASSAGES IN SAID BODY MEMBER COMMUNICATIVELY CONNECTING SAID SOURCE WITH EACH OF SAID CIRCUITS; SLEEVE VALVE MEANS DISPOSED ONE IN EACH SAID PASSAGE SLIDABLY OPERATIVE BETWEEN AN OPEN POSITION PERMITTING FLUID FLOW THROUGH 